I'm not sure of exact load bearing yet, I'm still looking about, but a cheap climbing frame you can buy for children, holds between 1000 pounds to 3000 pounds of weight, if I bought a prefab UV stainless steel kit, it would probably be much greater, concrete panels with steal frames and wire mesh, constructed into geodesic domes, can survive hurricane force winds, earthquakes, several feet of snow, and even falling trees, as noted in one companies profile history, but I'm just looking to get a sturdy steel or equivelant frame, perhaps with DIY supporting wire mesh, and some diy panels / filling material, either home made or prefabricated, whatevers best for the situation, so the range is broad, and I dont have the know how to give an accurate answer, but I did pull some key notes off a general geodesic structural integrity study on cadre, which came up with a 353 psi to 1228 psi max stress loads for a wooden frame geodesic greenhouse.
According to an online calculator I used,
353 Psi = 50832 Pound/Square Foot?
1228 Psi = 176832 Pound/Square Foot?
But I'm not sure if that's correct, it sounds alot for a wooden framed greenhouse lol, but here are a few of the paragraphs from the page.
"The sample structure is a 30 foot diameter, 4-frequency, icosahedron geodesic dome made from a wood frame of standard 2x6 lumber. The dome is intended as a greenhouse and is clad with polycarbonate panels which transfer external pressure loads to the wood frame structure but provide little structural support to the frame structure. Once the load sets have been developed using the panels, the loads will be re-distributed entirely to the frame structure and the panels themselves will be structurally neutralized or removed.
"The maximum stress in the panels is 450 psi vs. 1260 psi for the component model.This difference is because the panels automatically have clamped edges by virtue of their fixed connection to adjacent panels across the struts. That is a consequence of the plate finite element definition and cannot be easily worked around. The real structure of a strut and panel type dome is not likely to have clamped edge fixity so the component model would be a much better estimate of the real stress. Rank and color again, but this time rank on Beam stress with Von Mises stress. The maximum stress in any beam is 353 psi as compared to 1228 psi for the frame model. The 1228 psi is taken from the frame-only model results (see the previous table of von Mises beam stress above under the Case 3 column). This difference is the result of the panels which support the beams both vertically and laterally all along the beam due to the panel's in-plane stiffness. If one actually builds a integral structural panels with rigid structural interconnection then using the full model with panels makes perfect sense, but with cases where they are simple non-structural glazing panels (or even fabric) then separating the solutions into frame-only models and component panel models would be the recommended approach. The main idea is to use engineering judgment to set up the model and components in ways that most closely represent the actual structural configuration."
again, I'm not sure what kind of weight loads I'll get for a 8 foot diametere to 16 foot diameter UV stainless steal frame kit, but I'd imagine it's fairly high, though I may consider wood if cheap enough, using wire reinforced cement panels etc, with the correct steal frame, can support backfilling a dome house up to 4 feet deep without modification, as demonstrated on an ai dome house, and with modifications, can safely be buried completely -
https://www.aidomes.com/berming-or-burying/
but again, I dont want to use concrete or expensive materials, just the steel frame kit, or a similair prefab structure?, though I have considered other possibilities, like using earth bag construction too, I could probably build an earth bag root celler for a few hundred pounds, but I'm curious if a decent geodesic frame could work in tandem with other types of earth building, like earth bag construction?, to make my little holes in the ground a little bit safer overall, the dome acting more as emergency redundancy or whatever, and perhaps with the option of modification into a walipini greenhouse, or somthing like that, as I would be curious to see how well a dome walipini could work?, but generally, I'm looking for three basic structure types, root celler, a small living space, and an earth sheltered greenhouse of some kind, earth bags fit the bill best overall, but the materials for three structures will likely cost a bit?, so I'm hoping, with a strong prefabricated frame, I could build such in and around a hill area, or somewhat onto / and or beside the strong redundancy - emergency inner frame, in a modulated manner, to reduce the labour and costs overall, the labour atleast, though costs is still up for grabs I guess?, depending on the materials, but anyway, that's the general idea.
I could build an earth bag root celler for peanuts, right into the side of a hill, blending it into the landscape, and if I wanted, a simple earth bag bunker, could support a half sunken greenhouse, or I could just build that right into a slope following common practices, but that still leaves the living space, which i would like to ensure is atleast structurally sound / a little bit safer overall, and perhaps better able to be insulated or waterproofed, up to a more reasonable / slightly more comfortable extent, so that's why I'm wondering about dome frames, how i might be able to use steel framed geodesic domes, in tandem with other earth building methods, while utilising trench sloping and benching teqniques, and a bit of earth bag / rammed earth support work, or even simple lime and stone work etc?, leaving cob aside, the inner dome could be plastered with other coatings, to make it feel a bit more homey, and more weatherproof, if nothing else, smoothed, painted, lined with shelves, rather airy / permeable to start, and easy to add venting too etc, much better than sand bags, only really needing to worry about the minimal topsoil areas weight sloping above it, having the walls shored about via other means all around it, further, the geodesic panel spacing of the inner frame, requires less material to fill, it Is its own free standing structure, not weighing a whole lot, requiring no foundation, and much less wood / prefab paneling overall, also, I think this configuration, could pottentially make creating ventilation holes and such much simpler I would imagine?, as the space between the frame is initially naked, until its otherwise covered or filled with suitable materials.
At the cheaper end of things, I doubt that 1k to 3k of integrity, will support a four foot dugout and light soil cover, but still, I'm generally thinking of finding a nice balance Point in multi technique construction, somwhere in a hilly area, first digging a sort of pond dugout feature, in alignment with the surrounding land scape, placing my three domes in a semi circle near or facing eachother, and only minimally adding top soil, with a living roof like you say, in a manner that would give the appearance of little hills within the greater hillscape, if dug out in a sloped basin, the entrances could be small perforated culvert / risers perhaps?, or somthing like that, angled upwards to line up with the slope of a slightly deeper bermed section at the front?, and perhaps utilising a DIY French drain system, or a bit of local gravel?, though other than the run off / drainage, that's all optional, the geneeal idea, will be a series of altered sloping angles, and trench benching teqniques, rammed or rounded off perhaps?, and shored up with additional earth bag construction for strength, to prevent cave in, and reduce overall soil pressure, leaving the inner dome mostly free of surrounding weight, my domes could be placed in three such sections, structurally strengthened in some fashion or other themselves?, leaving the rammed earth / benched / earth bag surrounding walls secure, I'd backfill just enough soil to create living roofs, in alignment with the general landscape, I think this has some feasibility?, but such will require time, and a lot of digging, even if relatively cheap, so it may be better just to slot my builds neatly into stronger slopes on the hillside?, placing a few earth bags as up as security in the hill, and covering whats left sticking out just little bit,, with a thin coating of living material / and or grass, than to try tampering With loose souls?, but anyway, I'm just theorizing, to give you some idea of my build requirements.
sorry I cant be more specific on load bearing, but for very cheap, I can immediatly order a small dome climbing frame, between 1000 to 3000 pounds of integrity, if that gives you a starting point, which though relatively small in strength, could be combined with trench sloping and benching teqniques, earth bag support construction, and a sturdy set of prefab wire mesh supported panelings, of one sort or another, though DIY panels could also do in a pinch, if the primary soil support is a surrounding outer earthbag box, which I think is the best option?, the dome just needs to offer a little additional emergency protection, to act as a sort of emergency redundency, or failsafe so to speak, with a smooth and permeable inner surface to plaster and ventilate etc?, but regardless, as the cadre analysys shows, even a well designed wooden frame, can withstand much greater loads, and I could shell out on a half decent kit if I needed to, but what's the fun in that?, some designs are 10 k, some are 60 k, I'd rather use a cool thousand gbp at the most if I could manage it lol, less if possible, that kind of money is better spent elsewhere, since it's mostly a fun hobby project anyway, I'm not going to live in it on the grid style, but either way, I hope this is helpful, atleast you will have a better idea of what I hope to achieve overall, I appreciate / thank you for the time you took to respond, cheers, b.
here is the link to read it if your interested -
https://www.scribd.com/document/206668595/CADRE-Analysis-of-Geodesic-Dome
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